Struct Position

pub struct Position<'i> {
    input: &'i str,
    pos: usize,
}

A cursor position in a &str which provides useful methods to manually parse that string.

Fields

input: &'i str

pos: usize

Implementations

impl<'i> Position<'i>

pub fn new(input: &str, pos: usize) -> Option<Position<'_>>

Attempts to create a new Position at the given position. If the specified position is an invalid index, or the specified position is not a valid UTF8 boundary, then None is returned.

Examples

let cheart = '💖';
let heart = "💖";
assert_eq!(Position::new(heart, 1), None);
assert_ne!(Position::new(heart, cheart.len_utf8()), None);

pub fn from_start(input: &'i str) -> Position<'i>

Creates a Position at the start of a &str.

Examples

let start = Position::from_start("");
assert_eq!(start.pos(), 0);

pub fn pos(&self) -> usize

Returns the byte position of this Position as a usize.

Examples

let input = "ab";
let mut start = Position::from_start(input);

assert_eq!(start.pos(), 0);

pub fn span(&self, other: &Position<'i>) -> Span<'i>

Creates a Span from two Positions.

Panics

Panics if the positions come from different inputs.

Examples

let input = "ab";
let start = Position::from_start(input);
let span = start.span(&start.clone());

assert_eq!(span.start(), 0);
assert_eq!(span.end(), 0);

pub fn line_col(&self) -> (usize, usize)

Returns the line and column number of this Position.

This is an O(n) operation, where n is the number of chars in the input. You better use pair.line_col() instead.

Examples

enum Rule {}

let input = "\na";
let mut state: Box<pest::ParserState<'_, Rule>> = pest::ParserState::new(input);
let mut result = state.match_string("\na");
assert!(result.is_ok());
assert_eq!(result.unwrap().position().line_col(), (2, 2));

pub fn line_of(&self) -> &'i str

Returns the entire line of the input that contains this Position.

Examples

enum Rule {}

let input = "\na";
let mut state: Box<pest::ParserState<'_, Rule>> = pest::ParserState::new(input);
let mut result = state.match_string("\na");
assert!(result.is_ok());
assert_eq!(result.unwrap().position().line_of(), "a");

Trait Implementations

impl<'i> Clone for Position<'i>

fn clone(&self) -> Position<'i>

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<'i> Debug for Position<'i>

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.

impl<'i> Hash for Position<'i>

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl<'i> Ord for Position<'i>

fn cmp(&self, other: &Position<'i>) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl<'i> PartialEq for Position<'i>

fn eq(&self, other: &Position<'i>) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl<'i> PartialOrd for Position<'i>

fn partial_cmp(&self, other: &Position<'i>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

Tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

Tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

Tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl<'i> Copy for Position<'i>

impl<'i> Eq for Position<'i>